Method for purifying water

ABSTRACT

The invention relates to a method for purifying water by dissolving one or more soluble metal salts in the water to provide corresponding metal ions, by dissolving hypohalite into the water, and by regulating the residence time, and thus hypohalite concentration in the device using a venturi nozzle disposed between the metal generator and the hypohalite generator.

CROSS-REFERENCE

This application is a continuation of U.S. Ser. No. 11/252,106, filedOct. 17, 2005 (now abandoned), and U.S. Ser. No. 11/040,438, filed Jan.21, 2005 and issued as U.S. Pat. No. 7,147,786, both of which arecontinuations of U.S. Ser. No. 10/414,598, filed Apr. 16, 2003 and nowissued as U.S. Pat. No. 6,982,040.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the methods and apparatus for purifying andsanitizing water using a combination of halogenation and introduction ofmicrobiocidal metal species into the water. More particularly, theinvention relates to the systems and methods for combining purificationby chlorination and the introduction of biocidal metal ions into thewater using a single purification unit that is easier to install,operate, and maintain than are existing systems.

2. Description of Related Art

Purification of water by chlorination has been carried out for sometime. The introduction into water, in particular pool water, ofcompounds that dissolve or hydrolyze to form hypohalic acid, hypohaliteions, or both have known utility in disinfecting the water (and whoseuse is typically known as “chlorinating” the water). Chlorination iswidely used to protect swimmers and bathers in swimming pools, hot tubs,spas, and the like. It is a relatively safe, effective, and reliablemethod of water purification, and is familiar to many pool owners.

However, effective use of chlorination requires a rather high level ofskill and involvement on the part of the pool or spa owner. The waterchemistry must be carefully monitored and adjusted to maintainappropriate chlorine levels. Because the amount of hypochlorite ion inthe water degrades over time, the chlorine levels must be constantlyreplenished by addition of fresh chlorination chemicals. This requiresthat the pool owner frequently monitor chlorination levels andfrequently handle, measure, and add chlorination chemicals. Lack ofadequate care or insufficient skill in handling these chemicals can leadto an over- or under-chlorinated pool.

Highly chlorinated pool water is often uncomfortable to, and is thoughtto possibly have adverse effects on the health of, swimmers and bathers,decreases the useful life of swimwear, etc. For example, overlychlorinated water can cause burning sensations in the eyes and othermucus membranes, and is associated with a characteristic odor that somefind unpleasant. On the other hand, insufficient chlorine levels canallow the growth of pathogenic and nonpathogenic organisms to occur,which can create health risks and poor pool appearance.

In addition, hypochlorite generating chemicals are strong oxidizers,which can cause burns to human skin if not handled properly. It is alsopossible that exposure to aqueous hypochlorite generating chemicals cancause metal parts to corrode more quickly.

For all of these reasons, alternatives to chlorination, or at leastpurification techniques the decrease the amount of chlorination thatmust be used, have long been sought. The introduction of microbiocidalmetals into water to sanitize it has also been suggested for and used invarious water purification applications, such as in pools and spas. Inparticular, various methods of introducing metal ions, such as silverions or copper ions, into the water have been proposed. The use of theseions to purify, e.g., pool water, results in decreased need forchlorination. One method of introducing such ions into water that hasbeen proposed involves the use of sacrificial electrodes containingmetals corresponding to the desired ions, including alloys of silver andcopper, and electrolytically dissolving the metals into the water. Othermethods include contacting the water with substrates that have beencoated or impregnated with metal, soluble metal salts, or somecombination thereof. These methods can be difficult for pool owners tocontrol, and as a result, can sometimes provide unreliable control ofmetal delivery, and can cause stained surfaces when too much metal hasbeen delivered, or result in insufficient sanitation when too littlemetal has been delivered.

There remains a need in the art for a water purification system thatprovides the benefits of both metal ion purification and chlorinationtechniques, that is easy to install, maintain, and operate, thatprovides automatic control of chlorine levels in the pool, and thatrequires less handling of chlorinating chemicals by the pool owner.

SUMMARY OF THE INVENTION

This invention results from the combination of techniques for theintroduction of microbiocidal metals with the introduction ofchlorinating chemicals that uses a single device to dispense bothmaterials into the water in an automated fashion, to provide apurification system and method that is safe, effective, economical, andeasy to use.

The use of a single device simplifies installation and maintenance,since only a single vessel need be plumbed in and monitored.

The combination of microbiocidal metals with chlorination allowsdecreased levels of metal ion to be present, along with decreasedchlorine levels. As a result, there is decreased likelihood ofunpleasant or unhealthy side effects from either technique, such asstaining of pool surfaces, chlorine damage to hair and clothing ofswimmers and bathers, reduced opportunity to produce chloramines, etc.At the same time, the pool water is sanitized for a wide variety ofmicroorganisms by the use of multiple methods. In addition, the designof the system allows for the use of readily available tablets ofhypochlorite producing chemicals and automatic dispensing of appropriateamounts of chlorine to the water. This results in decreased need forhandling of oxidizing chemicals, and decreased need for monitoring ofthe pool water.

According to certain embodiments of the invention, purification of abody or stream of water is accomplished via an apparatus that includes ahousing having an inlet and an outlet. Water is directed into the inlet,which is in fluid communication with a metal generator, comprising ametal generating chamber containing media that introduces metalconcentrations into the water. The media may contain metallic materialwhich dissolves or disperses into the water, or may contain solublemetal salts, or combinations thereof.

At least some of the water flows through or otherwise contacts at leasta portion of the media, thereby acquiring some of the metallic material,generally in the form of metal ions. The metal generator may provide awater flow path that directs a portion of the inlet water through themetal generating chamber, where it comes into contact with the metalgenerating media, and another portion of the inlet water outside themetal generating chamber, so that it does not come into contact with themetal generating media. The metal generator may optionally provide aflow path whereby these two flows are mixed downstream of the media. Oneembodiment that includes these features contains a cartridge containingthe metal generating media, and which is disposed in a housing thatsupplies water through a manifold, wherein a portion of the water passesthrough openings in the cartridge, and another portion of the waterpasses through space between the cartridge and the housing containingthe cartridge, but does not substantially contact the media inside thecartridge.

The metal generating chamber is also in fluid communication with halogengeneration chamber, and with a venturi nozzle, which is itself in fluidcommunication with the halogen generation chamber. The halogengeneration chamber contains halogen generating salt, e.g., as sodiumhypochloride or other salt suitable for “chlorination” of water. Atleast a portion of the water directed into the inlet and passing throughthe metal generator can also flow through the halogen generator andcontacts the halogen generating salt, thereby introducing halogen intothe water. Another portion of the water from the metal generator isdirected through the venturi nozzle. This water generally does not flowinto the halogen generating chamber, but provides a pressure drop thatdraws water from the halogen generating chamber into the venturi nozzle,where it combines with the water from the metal generating chamber andexits the device for return to use. The water passing through thehalogen generator may be either untreated water from the metal generator(i.e., a metal generating chamber by-pass stream) or may be treatedwater from the metal generating chamber. In the first instance, thetreated water from the metal generating chamber will pass through theventuri nozzle. In the latter instance, the by-pass stream will passthrough the venturi nozzle.

In one embodiment, the invention relates to a device for purifying waterhaving an inlet and an outlet, comprising:

-   -   a metal generator, having an inlet in fluid communication with        the inlet of the device, and a first outlet and a second outlet,        and adapted to provide concentrations of one or more metals to        the water;    -   a halogen generator, having an inlet in fluid communication with        the first outlet of the metal generator, and having an outlet,        and adapted to provide concentrations of halogen to the water;    -   a venturi nozzle, having an inlet in fluid communication with        the second outlet of the metal generator, which is in fluid        communication with outlet of the halogen generator, and having        an outlet in fluid communication with the outlet of the device.

In another embodiment, the device contains one or more control valves,that can be used to regulate the flow of water into the halogengenerator, and thus the flow of water passing through the venturinozzle. Ensuring that the water flowing into the halogen generator isprovided at a point distant from the flow path from the halogengenerator to the venturi nozzle maintains adequate contact with halogengenerating media and adequate mixing with halogenated water. This helpsto ensure a consistent halogen concentration in the water In thealternative, or in addition to, this control valve, a control valve canbe used to directly regulate the flow of water from the halogengenerator to the venturi nozzle, by placing this control valve in theflow path between the two.

In another embodiment, the invention relates to the use of a controlvalve in conjunction with a venturi nozzle to control flow rate of waterinto a halogen generator. In this embodiment, the presence of a metalgenerator or metal generating chamber is optional, and can beeliminated. Water flowing into the device is divided into two portions,one of which passes through a control valve and into a halogengenerating chamber, while the other portion passes through a venturinozzle in fluid communication with an outlet of the halogen generatingchamber. The pressure drop between the halogen generating chamber andthe venturi nozzle (which is regulated by the proportion of inlet waterpassing through the control valve) draws halogen treated water from thehalogen generating chamber into the venturi nozzle. The combination ofcontrol valve and venturi nozzle thus controls the halogen concentrationof water leaving the device (and returning to the body of water fromwhich it was drawn, if such a return is done).

These and various other embodiments of the invention result in a methodand system that achieve the advantages of halogenation and theadvantages of microbiocidal metal ion purification, but vastly reducethe concomitant disadvantages of each. Further, the combination oftechniques results in a significantly more economical purificationprocess than is achievable with chlorination alone.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side and front view of one embodiment of a device accordingto the invention. FIG. 1A is a left side view along line L-L of frontview FIG. 1B.

FIG. 2 is a perspective view of the components of the embodiment of thedevice shown in FIG. 1, cutaway to show internal features of the deviceand water flow paths.

FIG. 3 is a graph showing vacuum drawn by the venturi nozzle in oneembodiment of the apparatus of the invention as a function of valveposition, for various flow rates of water through the apparatus.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

The methods and apparatus described herein can be used to sanitize andprotect water from the growth of microorganisms, such as bacteria,virii, fungi, algae, and the like. This sanitizing and protecting effectcan be used for water in a variety of applications, including swimmingpools, hot tubs, spas, as well as wastewater treatment facilities,cooling towers, and the like. The description below will focus onapplications for swimming pools, hot tubs, spas, and the like. Thosefamiliar with the art of water purification will be able to modify theteachings below to other water treatment applications without theexercise of undue experimentation.

In many cases, the metal introduced into the water will contain silver,copper, or some combination thereof, because of the recognizedbactericidal, viricidal, and algaecidal properties of these metals.Other metals, such as zinc, can also be introduced into the water, aloneor combined with the metals described above, to provide, e.g.,additional biocidal activity. The metals can be introduced as metallic,zero valence material, or as metal ions that can be introduced into thewater by dissolution of soluble metal salts, or by the dissolution ofthe metal itself. For example, silver ion can be introduced into thewater through the dissolution of silver nitrate, or through thedissolution of metallic silver as the result of conversion to silveroxide and subsequent conversion of the oxide to more soluble silverspecies. Copper ion can be introduced into solution through thedissolution of copper sulfate or copper chloride, for example. Mixturesof different salts, or of salts with metallic material, may be combinedtogether to provide the necessary concentration of metal ions in thewater.

Similarly, the halogen generating chamber will contain a salt of ahypochlorite, such as an alkali metal hypochlorite, such as sodiumhypochlorite. It will be understood, however, that additional oralternative halogen containing materials, such as materials containingbromide, iodide, hypobromite, and the like, or combinations thereof, canbe present in the water or in this chamber, and which can providesanitizing effects to the water being treated.

It will therefore be understood that, throughout this description, theterm “pool water” refers to water used in swimming pools, spas, hottubs, or other uses where purified water is required, unlessspecifically indicated otherwise. The terms “chlorination” and“hypochlorite” will be understood to refer to the use of hypohalite orhypohalic acid, or combinations thereof, to purify water. The terms“metal ion” will be understood to refer to any metal cations describedabove that provide protection against pathogenic or non-pathogenicorganisms in water.

One particular material suitable for introducing metal ions into thewater is a combination of soluble copper salt and metallic silver,deposited on a substrate, and sold under the name Nature²® by ZodiacPool Care, Inc.

The chlorinating material introduced into the halogen generating chamberwill generally be in the form of a solid, typically a solid salt thatwill dissolve easily in the water introduced into the chamber. In oneembodiment of the invention, the halogen generating chamber is adaptedto utilize commercially available hypochlorite salt tablets, which canbe stacked in the chamber. This approach is convenient for the poolowner, since it is easy to obtain the hypochlorite salt necessary toreplenish the device, and since replenishment need occur lessfrequently. In another embodiment of the invention, the halogengenerating chamber can be adapted to use proprietary hypochlorite salttablets, e.g., by shaping inner surface of the chamber to match theshape of the tablets. This provides the manufacturer with some controlover the type of tablets used, ensuring that the pool owner does not usetablets that are inappropriate for the particular purification use(e.g., ensuring that the pool owner does not use tablets designed for amuch smaller or much larger pool, thereby dispensing inappropriatequantities of hypochlorite into the water).

In general, sanitization of a body of water can be accomplished byremoving a flow stream from the water, passing this flow stream throughthe device of the invention, and returning the treated flow stream tothe body of water. Over time, and with a discrete body of water,dissolved hypohalite will have been carried by the pump and dispersedthroughout the body of water, where it remains active in sanitizing thewater. Similarly, microbiocidal metal ions are introduced when the flowstream from the body of water contacts the source for the microbiocidalmetal ions in the metal ion generating chamber, and returns through thebody of water. In either case, flow rates and residence times for theremoved flow streams are selected so that the water is in contact withthe metal ion generating material and or the source of metal ion for asufficient time to achieve the desired results, i.e., the desiredhypochlorite or metal ion concentrations. Alternatively, if a flowstream of water, rather than a body of water, is to be purified, theentire flow stream of water can be processed through the device.

In one embodiment of the device of the invention, water first enters themetal ion generating chamber. At least a portion of this water contactsthe metal ion generating material, which releases metal ions into atleast a portion of the water. A portion of the water that leaves themetal ion generating chamber then passes into the halogen generatingchamber, where it comes into contact with the halogen generatingmaterial, such as a solid hypochlorite salt. The water dissolves aportion of this salt, and thereby becomes chlorinated. Another portionof the water leaving the metal ion generating chamber passes through aventuri nozzle that is in fluid communication with both chambers. Theflow of water from the metal ion generating chamber creates a pressuredrop between the throat or constriction of the venturi nozzle and thehalogen generating chamber, thereby drawing treated water from thehalogen generating chamber into the venturi nozzle. The treated waterfrom the halogen generating chamber mixes in the venturi nozzle withwater exiting the metal ion generating chamber, and exits the devicethrough the outlet, which is in fluid communication with the outlet ofthe venturi nozzle.

The invention can be more clearly understood by reference to theattached drawings, which are directed to a specific embodiment thereof,and are not intended to limit the claims or to exclude other embodimentsof the invention consistent with this specification.

FIG. 1 is a left side view (FIG. 1A) and a front view (FIG. 1B) of awater sanitization apparatus 100 according to a particular embodiment ofthe invention. In these embodiments, the water purification apparatus100 includes a housing 102 associated with a base 101. Becauserelatively concentrated hypochlorite solutions will be generated withinthe housing, the housing is desirably at least primarily constructed ofchlorine resistant materials. ABS (Acrylonitrile-Butadiene-Styrene)plastic resin is one such suitable material, but any appropriatechlorine resistant material can be used. The housing material preferablycan be either opaque, or polished so as become transparent. The base 101is optionally detachable from the housing, and has apertures for aninlet 108 and an outlet 109, and preferably, for a pressure reliefvalve, shown in FIG. 2. The components of the housing are held togetherat least in part by a clamp 103, comprising a rear portion and a frontportion. The clamp provides structural integrity and ease of assembly tothe housing 102, and are preferably constructed of a strong, lightweightmaterial such as plastic or aluminum.

Openings in the top of housing 102 are covered by metal ion generatingchamber cover 105 and halogen generating chamber cover 107. Control ofthe amount of chlorine provided to the water is provided by chlorinemetering valve control 106.

FIG. 2 is a cutaway perspective view of the components of the watersanitization apparatus according to FIG. 1. The housing 102 includesports 110, 112 for installing and removing the metal generator 114 andhypochlorite, generally in the form of tablets (not shown). The metalgenerator port 110 is preferably sealed by a removable metal generatorcover 105. The halogen generation chamber port 112 is preferably sealedby a removable cover 107. Both the metal generator cover 105 and thehalogen generation chamber port cover 107 may be secured in place bythreaded collars 116 and 118, respectively, for ease of removal by thepool owner or servicing personnel; the covers and/or collars mayoptionally be tethered to the housing 102 to decrease the chance of losswhile the apparatus 100 is being serviced. The threaded collars 116and/or 118 may be equipped with mechanical stops and/or audibletightening indicators to ensure that the collars are positionedcorrectly. These features ensure that the tightening handles do notobstruct each other or access to the control valve.

To protect the components of the apparatus 100 from environmentalcontamination, and to prevent leakage of water, the apparatus is sealed.Either or both the metal generator port 110 and the halogen generationchamber port 112 includes a threaded port that couples with a cover in awatertight union that desirably includes a mechanical locking ring, ajacking ring, an o-ring, and a mechanical stop. For example, the metalgenerator cover 105 is rotated around the threaded end of the metalgenerator port until the cover 105 overcomes the mechanical lockingring, at which time the metal generator cover 105 is engaged at theappropriate tightness. The non-rotating “jacking” ring is desirablyinterposed between the cover 105 and the o-ring 120, and appliesvertical pressure while preventing the rotating cover 105 frommechanically stressing the o-ring 120. The o-ring 120 is interposedbetween the jacking ring and the mechanical stop, which is adjacent tothe base of the threaded end of the metal generator port 110.Compressing the o-ring 120 creates a seal that prevents water and othermaterials from escaping or entering the housing 102 through the metalgenerator port 110. The watertight seal is achieved in the same fashionwith respect to the halogen generation chamber port, the o-ring 120, andthe cover 107.

The housing may be include a top portion 142 separate from the bottomportion for ease of assembly and servicing, and these portions may alsoutilize a mechanical locking ring, jacking ring, and/or a housing o-ringto couple together in a water-tight fashion. Preferably, however, thehousing top and bottom portions are not easily disengaged after beingassembled together.

FIG. 2 also contains open arrows indicating the flow path of water into,through, and out of the device. Water 202 enters the housing 102 via theinlet 108. At least a portion 204 of this water is directed throughmedia contained in the metal generator 114. The metal generator 114 is acontainer, desirably cylindrical, that includes at least one vent 122and a media area 124. The bottom (inlet side) of the metal generator 114rests on or near the bottom of the metal generating chamber. In certainembodiments of the invention, some of the water 206 entering the metalgenerator 114 is expelled through the vent 122 without passing thoughthe media area 124. The inlet pressure causes the vented water 206 totravel around the metal generator 114, and the non-vented water 204 topass though the media area 114. Thus, the metal concentrations in thenon-vented water 204 are increased by contact with the media in themetal generator 114. After passing through the metal generator 114, thetreated water 208 is expelled though slots (not shown) at the top of themetal generator 114, and blends with the vented water 206 that has beenchanneled around the metal generator 114.

A portion 210 of the treated water 208 flows through valve 106 and isdirected to the halogen generating chamber through flow path inlet 126.The flow path outlet, from which water flows into the halogen generatingchamber, is disposed at a distance from the inlet of tube 128 (i.e., theoutlet from the halogen generating chamber). This ensures that inletwater is forced to flow up through the existing water in the halogengenerating chamber, and increases contact with the halogen generatingmedia, thereby preventing fresh untreated water from immediately leavingthe chamber. This, in turn, helps to ensure a relatively constantconcentration of halogen in the water leaving the halogen generatingchamber. One method of providing such a flow path is tube 131, having aninlet at opening 126 and an outlet (not shown) near the bottom of thehalogen generating chamber.

Water leaves this outlet and enters the chamber, where it comes intocontact with hypohalite, generally hypochlorite, which is generally insolid form, typically in the form of tablets or granules. Water remainsin this chamber for a time sufficient to dissolve sufficient hypohaliteto provide sanitizing effective amounts of hypohalite to the water. Asexplained above, the water is forced to flow through and mix with wateralready in the chamber, and to come into contact with halogen generatingmedia, before exiting the chamber. At steady state, the water level inthe halogen generating chamber is at the level of the inlet of tube 128.A portion 212 of the water in the halogen generating chamber is drawnfrom the chamber through tube 128 by the difference in pressure betweenthe water in the halogen generating chamber and venturi nozzle 130. Aportion 214 of untreated water 206 leaving the metal generating chamberpasses into the inlet 132 of venturi nozzle 130. The outlet of tube 130is located approximately at the throat 134 of venturi nozzle 130, wherethe pressure drop created by water 214 passing through the nozzle 130 isrelatively high. In outlet 136 of nozzle 130, the treated water from thehalogen generating chamber mixes with the untreated water from thenozzle inlet to form treated outlet water 216. This sanitized water canthen be used by, e.g., returning it to a pool or spa.

In the embodiment shown, separate cylindrical chambers are used formetal generation and for halogen introduction, as the circularcross-section of these chambers is better able to withstand the stressesintroduced by operating at pressure. In the event that the pressureinside the apparatus increases beyond desirable design limits, theapparatus is provided with a pressure relief valve 138, which allowswater to drain from the metal generating chamber, decreasing thepressure in the system until it returns to acceptable levels. Thepressure relief valve 138 can be mechanical and/or electrical, anddesirably operates when an internal pressure within the apparatusexceeds a preset value (“trigger pressure”). The trigger pressure can beimplemented mechanically or electronically, such as with a spring or anactivation switch. The pressure relief valve 138 is preferably set toactivate, i.e., to open, at the trigger pressure, within an acceptabletolerance (e.g., 50^(+/−)10 psi). In addition, drainage plugs 139 and140 provide for ease of draining the device, if desired, for shut down,winterization, replacement of halogen or metal sources, or shouldservicing be necessary. Assembly plug 141 closes an opening resultingfrom the molding process, and has no effect on operation of the device.

An advantage of the various embodiments of the water sanitationapparatus 100 is its ease of installation and maintenance. The housing102 is compact, allowing for installation in space restricted areas. Theinstaller couples the apparatus 100 with the source of the water to betreated by connecting a suitable water carrying conduit, such as a 2″PVC (polyvinyl chloride) pipe, to the inlet 108. The inlet conduit isfurther connected to the source of the water to be sanitized. Theinstaller then connects a second conduit to the outlet 109, for allowingegress of sanitized water.

The operator can also easily install or replace metal generator 114 andreplenish the hypochlorite generating material. To do so, the operatorsimply loosens the appropriate cover 105, and disengages the cartridge114. A new cartridge is engaged, and the cover is retightened.Similarly, the operator can simply loosen and disengage cover 107 andadd hypochlorite tablets as necessary, and reengage cover 107.

The design of the apparatus of the invention allows a single valve 106,which can be any suitable valve type, particularly a needle valve, tocontrol the amount of chlorination received by the water. This occursboth by regulating the flow rate into the halogen generating chamber,but also by regulating the volume of water that does not flow into thehalogen generating chamber, and therefore passes through the venturinozzle. This, in turn, regulates the pressure drop between the halogengenerating chamber and the venturi nozzle. FIG. 3 provides a graph ofvacuum drawn by the venturi nozzle as a function of valve position forvarious flow rates of water through one embodiment of the apparatus. Thegraph shows that, as the valve approaches a “closed” position (position0), the vacuum increases as more water is forced through the venturinozzle. As the valve is opened (valve position increases), the vacuumdecreases in an approximately linear fashion for almost all of the flowrates tested. This predictability provides easy and predictable controlof the residence time of water in the halogen generating chamber, andthus provides a very precise control of the hypohalite concentration inthe effluent water.

The foregoing description of various aspects, features, and embodimentsof the invention has been presented only for the purpose of illustrationand description and is not intended to be exhaustive or to limit theinvention to the precise forms disclosed. Many modifications andvariations are possible in light of the above teaching. For example, itshould be understood that although the present invention has beendescribed primarily with water flowing through the metal generator andthen through the halogen generating chamber, the principles of theinvention can be implemented conversely. The materials used for eachelement of the water sanitization apparatus are limited only by themechanical, electrical, and chemical properties of the materials.Although particular shapes, sizes and configurations are disclosed, manyother shapes, sizes, and configurations are possible without departingfrom the scope and spirit of the invention.

1. A method for purifying water comprising the steps of: providing awater purifying system comprising: a) an inlet for entry of water; b) ametal-generating media adapted to contact at least a portion of thewater in a system and provide concentrations of one or more metals tothe water; and c) a halogen-generating media adapted to contact at leasta portion of the water in the system and provide concentrations of oneor more halogens to at least a portion of the water, wherein themetal-generating media and the halogen-generating media are in fluidcommunication with one another; providing a flow path between b) and c);carrying at least a portion of water through said system via the flowpath; creating a pressure drop; and drawing water from thehalogen-generating media into the flow path; wherein an exit outlet isin fluid communication with the flow path, the exit outlet adapted toallow water to exit the water purifying system, whereby at least aportion of the water exiting the system is purified.
 2. The method ofclaim 1, wherein the metal-generating media and the halogen-generatingmedia are contained in a housing.
 3. The method of claim 2 wherein atleast a portion of the water entering the system flows through themetal-generating media, flows through the halogen-generating media, andenters the flow path to exit the system.
 4. The method of claim 2,wherein at least a portion of the water entering the system by-passesthe metal-generating media, flows into the halogen-generating media, andenters the flow path to exit the system.
 5. The method of claim 2,wherein at least a portion of the water entering the system by-passesboth the metal-generating media and the halogen-generating media andenters the flow path to move water from the halogen-generating media toexit the system.
 6. The method of claim 2, wherein at least a portion ofthe water entering the system flows through the metal-generating media,enters the flow path to move water from the halogen-generating mediainto the flow path to exit the system.
 7. The method of claim 2, whereinthe system is selected from the group consisting of: a pool and a spa.8. The method of claim 1, wherein at least a portion of the waterentering the system is directed to: (1) enter the metal-generating mediaand flow into the halogen-generating media; (2) by-pass themetal-generating media and flow into the halogen-generating media; (3)by-pass both the metal-generating media and the halogen-generating mediaand enter the flow path; (4) enter metal-generating media and enter theflow path; or (5) some combination thereof.
 9. The method of claim 1,wherein the system is selected from the group consisting of a pool and aspa.
 10. A method for purifying water in a system adapted to receivewater comprising the steps of: providing water to the system; providinga metal generator in communication with the water; directing at least aportion of the water into a metal generator; providing a halogengenerator in communication with the water and the metal generator;directing at least a portion of the water into a halogen generator;directing at least a portion of the water into a flow path adapted tocreate a pressure drop to move water from the metal generator or halogengenerator into the flow path; and directing at least a portion of thewater out of the system.
 11. The method of claim 10, wherein the systemis selected from the group consisting of pools and spas.